Slashdot Mirror
NASA Designs 'Ice Dome' For Astronauts On Mars (phys.org)
An anonymous reader quotes a report from Phys.Org: The "Mars Ice Home" is a large inflatable dome that is surrounded by a shell of water ice. NASA said the design is just one of many potential concepts for creating a sustainable home for future Martian explorers. The idea came from a team at NASA's Langley Research Center that started with the concept of using resources on Mars to help build a habitat that could effectively protect humans from the elements on the Red Planet's surface, including high-energy radiation. The advantages of the Mars Ice Home is that the shell is lightweight and can be transported and deployed with simple robotics, then filled with water before the crew arrives. The ice will protect astronauts from radiation and will provide a safe place to call home, NASA says. But the structure also serves as a storage tank for water, to be used either by the explorers or it could potentially be converted to rocket fuel for the proposed Mars Ascent Vehicle. Then the structure could be refilled for the next crew. Other concepts had astronauts living in caves, or underground, or in dark, heavily shielded habitats. The team said the Ice Home concept balances the need to provide protection from radiation, without the drawbacks of an underground habitat. The design maximizes the thickness of ice above the crew quarters to reduce radiation exposure while also still allowing light to pass through ice and surrounding materials.
that astronauts will face a frosty reception on Mars.
I am sure that your country's highly successful space program, that has done multiple successful manned landings on other celestial bodies, and sent many successful probes to land on Mars, knows much better. Which country was that again?
This, like most plans about survivability on Mars, is fantasy level design. Just have to carry the water in supply ships or bring it with you around each transport ship (once we make ships that do that) or mine the water from the Martian surface (hopefully it's about the same as what we need, right?).
I believe, the only way to live on Mars, in the forseeable future, is underground. That has enough problems to make it impractical in the next century. It's been particularly biting that In the 80's we thought we'd have flying cars and instead we got the "don't pokemon and drive" freeway warnings.
If we can get something long-term set up on the Moon, we can handle Mars. Humans haven't been willing or able to try yet. It should net some tasty govt grants though, eventually (eco-dome experiments primarily resulted in a terrible movie).
Often wrong but never in doubt.
I am Jack9.
Everyone knows me.
I still think they need to look into solar sintering based glass fiber production. Sinterable dust is all over on mars, and already loaded with melt temp reducing salts. The median bulk composition of Martian dust needs to be released for materials research, to see if viable glasses can be produced this way. (You just need a bead of glass and a centrifuge to spin off glass fiber. Even with the lower light levels, this should be doable on Mars. That gives the raw material for sandbag based habitat construction.)
So far though, I have yet to see a good bulk mineral assay of martian dust, only formulations for simulants that simulate texture for landings. That is not useful for evaluating glass quality for fiber production.
Someone hasn't been paying attention over the last few years.
The martian water tends to be 2 kinds:
So saline that it will literally burn your skin off on contact (because it is basically bleach).
Frozen, and buried under a lot of overburden.
The first kind avoids sublimation and freezing due to its high salinity. It is useless for astronaut/colonist use. Would require extensive reprocessing to be made useful. Not cheap.
The second kind avoids sublimation due to the pressure exerted by the overburden, and the frigid deep soil temperatures of Mars. Mining it requires removal of the overburden (strip mining), which is not cheap. Once exposed, it will begin sublimating immediately. A great deal will be lost to this form of evaporation, and the mine strip will be geologically unstable, due to the volatility of the ice. Not cheap.
Putting dirt into sandbags? Potentially very cheap.
... I do have to admit, this one seems the best thought out (it's been covered here on Slashdot before). The level of detail that they went into on their work was impressive, on every front. Some of the unique concepts are rather interesting, such as having the outer ice shell shaped as a fresnel lens, thus concentrating sunlight to higher levels in the interior. I also like the nested aspects of it - providing a large uninsulated (but pressurized) staging yard (quite useful, particularly once you start ramping up ISRU and need room for lots of industrial systems and feedstock/output stockpiles), and an insulated greenhouse/courtyard around the primary shelter (nice thought toward human factors, as well as small scale agriculture). Having the primary shelter be constructed on Earth and simply landed (with its interior space initially filled up with the hardware needed to make the outer radiation protection / pressure shell) hits all the right buttons as well. Having the "printer" slide along grooves in the shell it sprays out is also a lot more elegant of a design than many other potential alternatives.
Still, there's a massive amount of engineering and testing that would be needed to make such a thing. And a lot of in-situ demo missions as well for each aspect of the technology, especially the (no hardware design given) vaporization-based water recovery system, but up to and including a small scale inflate-and-print testbed.
For the love of Crom, am I the only one here who wants to keep the U.S. technologically competitive?
Arbitrary saline water is not "excellent for electrolysis", you'll end up destroying your electrolysis cells. Look at all the trouble they've had with the Elektron systems on the ISS, and that's under perfectly controlled conditions. Screwups are not acceptable on Mars. You can't just guess that things will be okay. For any potential ice resource, you need to have it very well quantified (and not just a tiny surface sample - and not just the water, but all of the solid matter it's mixed in with), so that engineers on Earth can create an accurate testbed for their proposed hardware to operate on.
Re, boring: have you ever seen the size of a TBM? Don't get me wrong, nuclear-powered Martian backhoes aren't exactly a dime a dozen, but that sure sounds cheaper than martian TBMs.
I have to agree with weird_w - the simplest means of radiation shielding is to use loose regolith (in regions where it's available in a deep enough layer... which aren't exactly rare, although they're not universal). Whether that's via bagging, binding with cement, binding with materials from Earth (a thermoplastic, epoxy, water, etc, optionally plus reinforcing fibers), or just simple loose dumping over a form, they're probably your easiest bet.
If you are advancing to the point where you're going to be doing in-situ water harvesting for electrolysis and drinking, however, something like the ice house is probably worth consideration. It does provide for much better human factors via transmission of (and fresnel concentration of) light, and allows for some limited agriculture (without requiring vast amounts of power generation for artificial lighting). It's easy to want to ignore human factors, but they're very real. Having people live their lives inside a cramped windowless can isn't exactly good for mental health or morale.
However, IRSU water is not a given. Pretending that harvesting of water is just "you go there and dig it up" is a vast oversimplification. To the point that even a lot of IRSU propellant proposals call for sending the hydrogen for the fuel from Earth even while they get the carbon and oxygen from the atmosphere. The atmosphere is a fairly constant, reliable, predictable fluid feedstock. The ground... isn't.
(And yes, technically you can get water vapor from the atmosphere, but the quantities it's available in are so tiny that most analysis writes off the concept due to the amount of air you'd have to move through the system per unit water recovered, and the mass of the system you'd need to do so)
For the love of Crom, am I the only one here who wants to keep the U.S. technologically competitive?
I assume you mean basalt fiber, not glass fiber. Quartz sand is not readily available on Mars.
Not every basalt is suitable for use in production of basalt fiber. I have no clue how well Martian regolith would suit, and I doubt anyone else does. Either way, it's a very energy intense process involving some pretty heavy hardware; you have to basically create a molten pool of basalt (aka lava) at about 1400C and blast it through tiny nozzles into air (which is extremely thin to begin with on Mars) moving at hurricane speeds.
Yes, the simulants like JSC Mars-1A are pretty poor. It's just sifted Pu’u Nene tephra. MMS is a bit better (not as weathered), but still, they just (roughly) match major elemental concentrations, they don't have any of the "Mars specific" things like hexavalent chromium, perchlorates, etc, nor do they guarantee particular mineral forms. And "roughly" is a key term to emphasize about the ratios. But for something where you're just going to be melting it down, that probably doesn't matter too much. Again, though, "Martian basalt", like basalt on Earth, is not a single universal thing; the dust from the particular site would need to be sampled and analyzed on its own.
Were you talking about fiber production for use as loose-fill reinforcing fibers (like are used in some types of concrete) or for making into cloth to make into bags? Either way it's probably just easier to send from Earth, at least in the early phases.
For the love of Crom, am I the only one here who wants to keep the U.S. technologically competitive?
The idea I had in mind is more akin to a high temp version of a cotton candy machine.
A central vessel at the spin axis is under the focal point of a Fresnel lens. A small shaker chute dispenses more dust to this crucible as material is removed. The crucible has two or three small holes through which material may be expelled, and it rotates at several hundred rpm. The mechanical stretching needed for glass fiber comes from the fiber hitting the side of the hopper, while the axis continues to rotate. This should produce a cotton wool like glass fiber, which should be workable into simple construction forms.
Due to the aridity, even water soluble glasses may end up being useful, if nothing else but for creating dust collection filters for atmospheric concentrators.
Have you seen any basalt fiber production process that actually works like that? I haven't. I would hesitate to say that it "should", because if it did, I'd expect people to use it.
As for the heating: it's hard enough to melt things like zinc with sunlight. Hot enough to melt basalt with just sunlight? On Mars? Now that's a very tall order.
Again, you keep saying "glass". Mars is basaltic, not rhyolitic. You're talking basalt fiber. And the main mechanical properties you need for most applications are tensile/yield strength and young's modulus, as well as creep and flexural behavior. And getting the desired properties means using an appropriate source material.
And I'm still not sure for what purpose you brought this up in relation to building habitats. Basalt fiber reinforced concrete is very much a real thing (I'm actually getting ready to build a basalt fiber reinforced house), but again, it'd be much simpler/cheaper/more reliable just to import your fiber from Earth, at least while one is just getting a colony established.
For the love of Crom, am I the only one here who wants to keep the U.S. technologically competitive?
When I say "glass", it is not necessarily "amorphous silicon dioxide". It is more " amorphous phase metal oxide". It need not be silicon oxide.
"glass" refers to its structure, not composition.
glass thus does not require silicon to be created. an example is oxide glass, made from 90% alumina.
there ARE clay formations and claystone formations on mars, which would produce viable glasses.
As for solar only based sintering (on mars), I still think it is doable, and could be simulated on earth with appropriate feedstocks, and occultation of the Fresnel lens to model the 60% or so reduction of solar intensity.
A Fresnel lens from a big screen rear projection TV produces a focal point suitable for this purpose on earth. (It can melt pure silicon oxide without a flux, which has a vitreous transition temp of 1475k) We would need a significantly larger one on mars, but still within the realm of being sent there rolled up in a shipping tube.
I don't doubt that it's possible; it's the rate that's the issue. Not knowing what your goal is (aka, what the fibers are for), it's hard to get a sense of how rapidly you'd need to melt it, and thus how big of a system you'd have to have.
For the love of Crom, am I the only one here who wants to keep the U.S. technologically competitive?
I just wanted to thank Rei and wierd_w for some topical, intelligent hilarity.
Seems like most of the comments on slashdot these days are made by dumb people, are not topical to the thread they're posted in, and usually have to do with Trump or Clinton.
It's good to see some engineers getting lippy with each other over things like the definition of glass. That's why I come to slashdot - to find people smarter than me arguing about interesting things.
That would be Russia. You know, the country that beat the US in most space milestones, yet is somehow lacking in all those supposed space spinoffs.
Well, you mean the Soviet Union. At its peak the Soviet Union had about the same population as the US has now: 293 vs. 319 million. Russia currently has a population of 143 million -- still a big country, but laboring under both a smaller population, smaller per capita wealth, and a system that funnels that bulk of that wealth to a small number of kleptocrats.
The thing that makes the difference in any technology race is human capital. You need large numbers of people, and you have to make good use of them. Hundreds of millions of uneducated peasants or unskilled laborers adds nothing to a country's technological might.
What made the US a powerhouse in the middle twentieth century was a large, educated middle class. Sure, Singaporeans are better educated than we are, and it shows in their outsized tech footprint for their population; but that population is only five million. The country to watch is India, which has a middle class larger than the US middle class. And it's the middle class you want to pay attention to, because there's where you have the combination of education and numbers necessary to be a tech innovator. When it comes to brains you need BOTH sheer numbers AND quality.
Unfortunately the US middle class isn't what it used to be. In 1968, we had a GINI coefficient of 38.6. GINI is a measure of income inequality; that would put us roughly in the neighborhood of Japan today. As of the last available data US GINI was approaching 48 and still climbing rapidly. That puts us in the neighborhood of Mexico, heading for Zimbabwe territory. Even Russia has more economic equality than we currently do.
It's not inequality per se that's the problem. There is nothing inherently bad about rich people having lots of money. In fact all other things being equal that's a good thing. But if you want a middle class family to put even one of its on average 3 children through a four year engineering degree, that family is going to have to come up with a lot of dough. The total costs of a four year STEM degree is $180k, and the median household income is just a hair over $50k. And while there is considerable public and private support, the cost of higher education has risen over the past thirty years while middle class incomes have stagnated. Income stagnation wouldn't make any difference if prices stagnated too, but they haven't. Some things like TVs and cars have got cheaper in real terms, but other things like education and health care have risen faster than inflation. People are getting priced out of the education market, and that reduces the net size of our national tech brain power.
If we want to remain a world leader in technology and science, we need to maintain and support the army of brains it will take to make that happen. In the 60s there was a distinct understanding that this undertaking was a national priority. Americans today take tech leadership as some kind of birthright, which it is not. That means we have to expect to fall behind India, China, and whatever kind of European Common Market remains after Brexit.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.